The Spring Framework A quick overview

The Spring Framework 1. Spring principles: IoC 2. Spring principles: AOP 3. A handful of services 4. A MVC framework 5. Conclusion

1. Spring principles: IoC Inversion of Control: an object interacts with its environment Objects are « plugged » one in another The environment is set up by the container instead of the object itself

1. Spring principles: IoC Without IoC: With IoC

1. Spring principles: IoC Useful for separating dao and business layer Useful for separating controllers and business layer The code is more extensible, easier to read, and modules/layers can easily be replaced

2. Spring principles: AOP Separates the core business code from the aspects we wrap around it: security, transaction management, … Through AOP, we add transversal functionalities to objects (ie not directly related to the code it contains)

2. Spring principles: AOP Without AOP With AOP

2. Spring principles: AOP Useful for automatic handling of transaction with Hibernate Useful for Acegi (automatic credentials checking before executing some methods) Code smaller, easier to read (not polluted by transversal aspects not directly relevant)

3. A handful of services

DAO support: Spring offers templates classes to deal with a Hibernate/JDBC/… connection Exception translator: all the proprietary Hibernate/JDBC/… exceptions are catched by Spring, and rethrown as Runtime non-specific consistent exceptions Hence the DAO code is not dependant on the underlying datasource!

3. A handful of services Many ORM tools are supported: Hibernate, JDO, Apache OJB, iBATIS Templates using IoC to reduce the amount of code in the DAO objects

3. A handful of services Support of RMI Very easy to expose and connect to webservices Support of JMS JMS templates, JMSException translation

3. A handful of services

A mail abstraction layer – Templates Jobs scheduling (Quartz, Timer) – Cron – Business layer unaware

4. A full MVC Framework Clear separation of roles: controller, validator, form object, Dispatch servlet, View resolver, … Extensible and adaptable Several views of a result (pdf, excel, html, …) Can be wired (possible to use transparently the IoC pattern)

4. A full MVC Framework Can be used with other frameworks: JSF, Struts, Tapestry, Webwork Completely transparent: no need to change anything in what is done by these other frameworks

4. A full MVC Framework

5. Conclusion Learning curve XML configuration & annotations Tiny Open-source and free Active development Linked with several important Java projects (Hibernate, Acegi, …)